This is effectively a Leg-Lift and a Crunch combined. Lie flat on the floor with your legs straight out and feet together and your arms over your head.

Lift your legs to about ninety-degrees from the floor by engaging your lower abs while simultaneously rotating your arms to be along your sides and doing a crunch. The result is your legs are almost straight up in the air, your upper back is several inches off the ground, and your hands are at the ground near your glutes.